Short-yardage stats explain why Jacobs still sitting

Frank Gore has converted four of his past five opportunities on 3rd- or 4th-and-short. (AP)

Why in the world haven’t the 49ers used short-yardage behemoth Brandon Jacobs this season?

The 264-pound back referred that question to Jim Harbaugh this week, but the answer can be found in the numbers: The 49ers are doing just fine in short-yardage situations without him.

San Francisco has converted 9 of 13 opportunities (69.2) when its called run plays on third- or fourth-and-short (two yards or fewer) situations this season. In fact, the 49ers have collected first downs on nine of their past 10 such short-yardage situations, including seven in a row.

Not surprisingly, Frank Gore has been the primary short-yardage back. Gore was stuffed for no gain on his first three short-yardage runs this season, but has since rebounded to convert four of five runs, a stretch that includes a two-yard score on 4th-and-1 against the Jets in Week 4.

The numbers bode well for the 49ers, but they suggest Jacobs may not see the field unless there’s an injury, or a downturn in San Francisco’s short-yardage success.

Jacobs, who has yet to play a snap this season, was a healthy inactive for the 49ers’ Week 8 win at Arizona.

** The 49ers have called four pass plays on third-and-short this season and converted none. The tally: two sacks, an incompletion and a one-yard completion on 3rd-and-2.